Field
The described embodiments relate to techniques for monitoring and communicating with a battery pack. More specifically, the described embodiments relate to techniques for charging a battery based on stored representations of characteristics of a battery in the battery pack.
Related Art
The ever-increasing functionality and performance of portable electronic devices is, in part, due to advances in power sources, such as battery packs. Modern battery packs in portable electronic devices typically include circuits that monitor characteristics of the battery packs, such as the voltage across a battery in a battery pack, a charging current, an internal impedance, the available capacity, etc. This information is typically communicated to a host portable electronic device via one or more signal lines.
In addition, for safety reasons, it is often important to at least periodically monitor the temperature of the battery pack and/or the battery in the battery pack. For example, the temperature of the battery pack (and, more generally, a temperature state of the battery pack) may be monitored during charging using a temperature sensor in the battery pack.
If the temperature sensor can be accessed directly, this temperature monitoring may be conducted using an electrical circuit external to the battery pack. However, in many battery packs the temperature sensor cannot be accessed directly. Instead, the battery-monitoring mechanism may be interposed between the temperature sensor and the external electrical circuit. As a consequence, the temperature (or temperature state) is conveyed by the battery-monitoring mechanism on the signal lines along with other characteristic information.
For example, the temperature (or temperature state) may be included in a digital value output by the battery-monitoring mechanism as opposed to an analog signal. However, the use of a digital representation can pose challenges when controlling the charging of the battery pack, especially in the event of a hardware or software failure that disrupts the communication of the digital value. In these circumstances, the temperature of the battery pack cannot be monitored during charging, and safety issues can arise.